Abstract. To realise an Ambient Intelligence environment, it is paramount that applications can dispose of information about the context in which they operate, preferably in a very general manner. For this purpose various types of information should be assembled to form a representation of the context of the device on which aforementioned applications run. To allow interoperability in an Ambient Intelligence environment, it is necessary that the context terminology is commonly understood by all participating devices. In this paper we propose an adaptable and extensible context ontology for creating context-aware computing infrastructures, ranging from small embedded devices to high-end service platforms. The ontology has been designed to solve several key challenges in Ambient Intelligence, such as application adaptation, automatic code generation and code mobility, and generation of device specific user interfaces.

Current workflow languages for web services suffer from poor support for separation of concerns. Aspect-oriented software development is a well-known approach to improve this. In this paper, we present an aspect-oriented extension for the WS-BPEL language that improves on current state-of-the-art by introducing an explicit deployment construct, a richer joinpoint model, and a higher-level pointcut language. In addition, the supporting technology is compatible with existing WS-BPEL engines. Classification. Business process modeling and analysis, processes and service composition

Abstract. A software design is often modelled as a collection of UML diagrams. There is an inherent need to preserve consistency between these diagrams. Moreover, through evolution those diagrams get modified leading to possible inconsistency between different versions of the diagrams. State-of-the-art UML CASE tools provide poor support for consistency maintenance. To solve this problem, an extension of the UML metamodel enabling support for consistency maintenance and a classification of inconsistency problems is proposed. To achieve the detection and resolution of consistency conflicts, the use of description logic (DL) is presented. DL has the important property of being a decidable fragment of first-order predicate logic. By means of a number of concrete experiments in Loom, we show the feasibility of using this formalism for the purpose of maintaining consistency between (evolving) UML models.

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System and Software Engineering LabVrije Universiteit Brussel Maja.D'Hondt @vub.ac.be Viviane Jonckers System and Software Engineering LabVrije Universiteit Brussel Viviane.Jonckers@vub.ac.be ABSTRACT Software applications often consist of implicit knowledge for making decisions or giving advice in addition to objectoriented functionality. A rule-based system can be employed for representing and reasoning with this knowledge. Although several hybrid systems exist that combine objectoriented programming and rule-based reasoning, a survey we conducted reveals that both paradigms are not well integrated and programs are tightly coupled.We propose hybrid aspects for integrating object-oriented programming and rule-based reasoning. As expected, hybrid aspects specify join points where normal execution is interrupted and advice is executed. However, since two different languages are involved, we need join point models for both and advice that activates both. As such, we complement a simple join point model for object-oriented programming with a join point model for rule-based reasoning. Hybrid advice is independent of the interrupted language and sup-ports sending messages as well as activating rules. It uses values of either language transparently.We present OReA, an implementation of hybrid aspects for weaving Smalltalk and a rule-based system. We discuss and illustrate two applications of hybrid aspects.